Radio frequency (RF) power amplifiers are used in wireless transmission devices to amplify an RF signal for transmission. Power consumption is a concern for users and manufacturers of these wireless transmission devices. One of the factors in determining the power consumption in such devices is the direct current (DC)-to-RF conversion efficiency of the RF power amplifiers. DC-to-RF conversion efficiency may be a measure of how much DC power is converted into RF energy.
High DC-to-RF conversion efficiencies have been demonstrated at a unit-cell level. However, when RF power amplifiers employ multiple unit cells, efficiency degrades due to these devices failing to provide desired impedance matching across fundamental and harmonic operating frequencies.